Method of energizing filaments



A. NYMAN |:-:'r AL 1,870,960

METHOD OF ENERGIZING FILAM-ENTS Filed Marn 18. 192s 2 sheets-sneer 1 Aug.A 9, 1932.

Aug. 9, 1932.

A. NYMAN ET AL METHOD OF ENERGIZING FILAMENTS Filed Maroh 18, 1926 2 Sheets-Sheet 2 @N96 .u .Y su@ uw n I Ud 1 N. a P m. a. By Q 0 u WM .w m mlllm-IUHH A TTORNE Patented Aug. 9, 1932 l UNITED simeri-isv :PATENT oFFicE ALEXANDER NYMAN ANn GORDON v. Pnoii, OFNEW YORK, Y., AssIGNORs To DUBILIER cONnnNsER CORPORATION, vor NEW YORK, Y., A CORPORATION or DELAWARE 4METHOD OF ENERGIZING- FILAMENTS Application filed March 18, 1926# Serial No. 95,723.

Our invention relates broadly to the operation of electron tubes from a source of alternating current and more particularly to a system of supplying the filament electrodes 5 of a plurality of electron tubes from an alternating current power source without the setting up of undesired disturbances in the electron tube circuits which normally interere with the operation of such tubes in a signal receiving circuit.

One of the objects of ourinvention is to provide a system for delivering alternating current to the lament circuits of electron tubes having means Jfor reducing the tendency of the filament electrodes of th-e several elec'- tron tubes from periodicallv varying in temperature upon the reversal of current of the alternating ,current power source thereby reducing the tendency of the electron tube circuits to responding to disturbances in the power supply system. A

Another object of our invention is to provide a power supply system for the circuits of electron tubes having means for smoothing out the alternating current supplied to the tube circuits independently .of ilter systems heretofore employed.

Another object of ourinvention is to provide a current supply set for a filament electrode of a signal receiving` electron `tube apparatus having means for maintaining the ilament electrodes at a substantially con-y stant temperature when the energy is sup- Y plied from the alternating current power source.

Still another object of our invention is to provide an alternating current power supply system Vfor the filament electrodes of a plurality of electron tubes wherein the electron emission from the filament electrodes `is maintained substantially constant independent of reversals in current of the alternating current power supplyV system whereby quiet operation of the electron tube circuits in a signal receiving system mav be obtained.

A further object of our invention is to provide a current supply system for operating the filament electrodesV ofa plurality of electron tubes from an alternating curent power supply source with means for deriving a hereinafter following by reference to the heating power from the alternating current which isjsubstantially constant independent of the normal reversals in current of thealternating current source for eliminating the disturbances arising in the sensitive electron tube Vcircuitsdue to the periodic changes in direction of thecurrent of the source.

Other and further objects of our invention will be vunderstood from the specication 6.0 accompanying drawings, wherein:

Figure l is a theoretical view showing the normal heating power obtained in the lila-j ment circuit of aplurality of electron tubes when current is supplied Vfrom an alternating current power source; Fig. 2 is a theoretical view showing the more constant heating pow? er which is obtainable with the shaping ofthe characteristic curve of the current supplyl in accordance with our invention; Fig. 3 is a diagrammatic view illustrating a circuit arrangement embodying-the principles of our invention Fig. 4 is a view of .a number of characteristic curves showing the several currents existing in the current supply set of 75 our invention; and Fig. 5 illustrates a complete receiving system including a plurality of electron tubes having the filament 4circuits, thereof supplied from the current supply set of our invention.

I-Ieretofore in the art one of the diiiculties in operating electron tube .amplifying systems with power derivedfrom analternating current sourcehas been the Y. amplification of the hum of the alternatingcurrent in the receiving ,apparatus -to ,a greater l degree than` the amplification of the signaling energy. The disturbances which are set up in the elec- Y tron tube circuits arise from the periodic reversal in the current in the power supply system. Where the filament electrodes of a pluf rality of tubes are heated from analternating current source the filaments tendto periodioally change in temperature due to reversal in the direction ,of current. The variationv in 95 filament temperature results in the production of a hum in the reproducingmeans which connectwith the electron tube circuits. By

f our invention weprovide a currentgsupply set having means forsecurmg an alternating cur-` '100 rent which is so shaped in its characteristic curve as to secure a substantially constant heating power. A circuit arrangementis provided whereby the current which is supplied to the filament circuits substantially approaches a rectangular wave 'form which tends to produce a substantially uniform heating power eliminating the periodic vari-v ation in electron emission. The current supply set is provided with circuits tuned `to the funda-mental frequency'of the available alternating current supply and tuned to amultiple of the fundamental frequencyfor cornbining the effects of the. currents of the separated frequencies for producing a substantially rectangular wave form for developing uniform heating powerin the filament circuits of the electron tubes which are operated from the alternating current source. Y

Referring to the drawings inmore detail, referencecharacter l designates the vsine'wave characteristic curve of the commercial alternating current. Reference character'2 shows the normal hea-ting power for thelament electrode of an electron -tube which isenergized from the alternating current designated by curve l. It will be observed that the heating. power passes through periodic and sudden increases and decreases resulting in changes in the electron emission of the filament. By your invention we so shape the characteristic curve of the alternating current supply as shown in 2 at lcathat a heating power in accordance with curve 2a is obtained which does not 'have the abrupt increase and decrease in amplitude as is true in the case of curve ,2 of Figl.

In Fig. 3 we have illustratedone embodiment of our invention where the `current supply terminals are designated at 3 for delivering alternating 'current to the primary win ding `tof transformer T1 having secondary winding 5 for connection to the lament circuits of the electron tubes of the signal receiving apparatus. supply circuits at 3, we provide connections ".7 which connect through a. tuned system including condenser 8 and inductance ,9 with the primary winding 10 of transformer T2. The system 8--9--10 is tuned tothe frequency of the commercial alternating current supply Vwhich for the purpose of describing the invention may be considered as cycles.,v The transformer T2 has its secondary ll connected in series with the loa-d circuit and istuned by means of condenser 12 and ind-uctance 13 to a multiple of the supply frequency and for the purpose of describing the invention we have indicated this frequency to be 180 cycles.

As represented in Fig. 4 the characteristic of the voltage across the secondary winding p5 of transformer .'I"1 is designated :by curve 14.

.By reason of the tuning of theseveral circuits in the current .supply .set .the normal voltages existent across the Ysecondary winding ll `orf Shunted across the current transformer T2 are shown by curves 17 and 18 which result in a voltage having a characteristic wave form l5. The combined resultant of the voltage delivered to the output circuit is substantially rectangular in shape as designated at 16.

In illustratingthe connections of the current supply set with the electrontube circuits of aradio receiver, I have shown in Fig. 5 the vcomplete 'alternating-current power 'supply setv at 27 for supplying the filament heating current to electron tubes 22, 23, 2st, 25 and 26 of the signal receiving circuit. The output of the current su ply set is connected across terminals@ to tie iilainent circuit 30 of the receiving apparatus. Y

We have illustrated the signal receiving apparatus as constituted by a radio receiving system having an antenna 28 with'ground connection 29 and including a primary winding 3l ofl a couplingtransformer having secondary 21 connected to the signal receiving apparatus, but it will be understood that any electron tubel system may be operated with the apparatus of our invention and that the circuit arrangement illustrated is merely for the purpose of explaining one of the numerous applications of our invention. The plate potential for the several electron tubes 22, 23,

24, 25 and 26 is vsupplied through a rectifier 32.

The shaping of the alternating current before it is impressed upon the lilament circuit 3,0 avoids the periodic changes in temperature oi the .filament electrodes, thereby decreasing the ,tendency of theelectron tube circuits to amplify the hum of the alternating current.

Vhile we have shown the current supply set as having a portion of its circuit tuned to the third harmonic of the supply frequencywe desire that it be understood that the circuits ,may be tuned to other frequencies and that the purpose of our invention is to broadly set forth .the principles lof shaping the alternating current wave. form for supplying a su-bstantially uniform heating power to the {ilament circuits of an electron tube system.

IVe desire that it be understood that other modifications may be made and that no limitations upon the invention are intended other than those imposed by the scope of the appended-claims. Y

What we claim and desire to secure by Letters Patent of the United Statesis as follows v, l. In a current supply set for heating the filament of .a plurality of electron tubes, the combination of .a source of alternatingY current, means for supplying said alternating currentto the filament `electrodes of a pluralvity of electrontubes, and means for imparting a .substantially rectangular shape to the V wave formof vthe alternating current thus supplied to :.said filament electrodes for securing asubstantially constant heating power tor sai-d filament electrodes.

` 2. ,Means for enengizingl the Ycathode of .an

electron tube from a source of alternating current, comprising in combination with a source of alternating current, an electron tube, a cathode circuit for said electron tube, a. transformer for delivering alternating current from said source to said cathode circuit, andmeanssupplementingsaidtransformer for shaping the wave form of the alternating current supplied to said cathode circuit for reducing the tendency of abrupt variation in the energizing power of the cathode circuit.

3. A system for heating the filament electrodes of electron tubes comprising in combination aI source of alternating current, a circuit including the filament electrodes of electron tubes, means for delivering alternating current from said source to said circuit, and

means supplementing the connections of said first mentioned means for imparting a substantially rectangular wave form to the alternating current delivered to said filament electrodes for deriving a substantially constant heating power for said filament electrodes from said source of alternating current.

1f. In a system for heating the filament electrodes of a plurality of electron tubes, the combination of a source of alternating current, a plurality of electron tubes having filament electrodes disposed in a common supply circuit, transformer for delivering alternating current from said source to said common supply circuit, and means supplementing said transformer for imparting a substantially rectangular shape to the alternating current delivered to said common supply circuit for reducing the tendency of the filament electrodes of said electron tubes to vary in their electronic emission. v

5. A system for heating the filament electrodes of a plurality of electron tubes comprising in combination a source of alternating current, a plurality of electron tubes having filament electrodes disposed in a com- Y mon supplyv circuit, a transformer for delivcringalternating current from said source to said common supply circuit, an auxiliary transformer electrically connected with Said first mentioned transformer and providing means for imparting a substantially rectanguiar shape to the wave form of the current delivered to said common supply circuit for maintaining a substantially constant condition of electronic emission of said filament electrodes. Y

6. A system for heating the filament electrodes of a plurality of electron tubes com-` prising in combination a source of alternating current, electron' tubes having-filament electrodes connected to a supply circuit, a transformer having coupled primary and secondary circuits for delivering alternating current from said source to said `supply circuit, asecond transformer having coupled primary and secondary circuits connected with said first mentioned transformer for imparting a substantially rectangular shape to the wave form of the alternating current delivered to said supply circuit for obtaining a substantially constant heating power for the filament electrodes.

7. A system for heating the filament electrodes of electron tubes comprising in combination a source of alternating current, electron tubes having filament electrodes connected to a supply circuit, a transformer having coupled primary and secondary circuits, for delivering alternating current from said source to said supply circuit, an auxiliary transformer having coupled primary and secondary circuits with the primar 1 circuit thereof tuned to the frequency of said source and Vconnected with the primary circuit of said first mentioned transformer and the secondary circuit thereof tuned to a multiple of the frequency of said source and connected with the secondary circuit of said first mentioned transformer for imparting a substan- Y tially rectangular wave shape to the alternating currentdelivered to said supply circuit for maintaining a substantially constant heating power for said filament electrodes.

8. A system for heating the filament electrodes of a plurality ofelectron tubes comprising in combination a source of alternating current, a plurality of electron tubes having filament electrodes disposed in a commonv supply circuit, a transformer having coupled primary and secondary circuits, for delivering alternating current from saidsource to said common supply circuit. Van auxiliary transformer having coupled primary and secondary circuits with the primary circuitthereof tuned to the frequency of said source andconnected with the primary circuit of said first mentioned transformer and the secondary circ-uit thereof tuned toy three times the frequency of said source for imparting a subv stantially rectangular shape to the wave form of the alternating current delivered to said common supply' circuit for maintaining a substantially constant heating power for the filament electrodes of said plurality vof electron tubes.

9. The method of heating the filament of a vacuum tube which consists in utilizing an alternating current, altering the wave form thereofto become substantially rectangular and applying the resultant to said filament.

In testimony whereof we affix our signatures.

ALEXANDER ,NYMAN GORDCN V. PECK. 

